Automatic telephone system



July 12, 1932. R. HOEFERT ETAL AUTOMATIC TELEPHONE SYSTEI 2 Sheets-Sheet 1 Filed Feb. 20. 1931 M m x N g Q 12, 1932- R. HOEFERT ETAL AUTOMATIC TELEPHONE SYSTEM Filed Feb. 20. 1931 2 Sheets-Sheet 2 -Im REinZ-LUZEZ HETEET Km ln cuacK WM Fl Luz-r1 Patented July 12, 1932 UNITED STATES REINHOLD HOEFERT, F BERLlN cflARLoTTENBURG,

AND E'UET woLnAcK, 0E BERLIN,

GERMANY, ,ASSIGNORS To SIEMENS & HALSKE AKTIENeEsEtLscHA TmE sIEMENs- STADT, NEAR BERLIN, GERMANY AUTOMATIC TELEPHONE SYSTE Application filed February 20, 1931, Serial No. 517,292, and ill Germany April 16, 1930.

- of various directions over switches with free hunting. In these devices a switching over is effected after the seizure of a line of a certain direction and a setting of a group selector over this line by a simultaneously connected auxiliary stepping switch, byv

which switching over the preceding free hunting switch is set to a line group of the desired direction.

The object of the present invention is the production of a circuit which shall be more simple and reliable, compared to known arrangements for the selection of a line of a certain traffic direction. This is achieved in that, by special procedures at the calling station, a free huntingswitch, determining the traffic direction, is set on to'a line of'a certain trafiic direction.

By the device according to the invention the difficulties experienced in the known arrange ments are overcome, such difliculties arising when the connections effected, according to the various directions, are of a varying value, and metering of the connections, correspond ing to this value, is to be made. The inven tion shows also apractical manner in which the solution of this problem can be made in that it providesa special metering device for each traflic direction which is connected up by the switching means, determining the direction.

Two embodiments of the invention are shown in the drawings: Figure 1 shows the manner in which the setting is effected by a first preselector on to a line of a certain traffic direction and Figure 2 the manner in which the switching procedures are eifected by a second preselector. The arrangement,

according to Figure 1, operates in the following manner.

When the subscriber N1 lifts his receiver the relay R1 is energized over: earth, battery,

winding I of relay X, relay R1, contact 1t1,

subscribers line loop, contact 2251, resistance W1, winding II of relay X, earth. Relay X is not energized in this circuit'as it is constructed as a difierential relay. Relay R1 closes its contact 311 with the result that a circuit is closed for the rotarymagnet D1 over: earth,.battery',- switch wiper m, contacts M1, 4251, rotary magnet DI, interrupter Url, earth. The wipersof the preselector arethen advanced until they have found a free succeeding-switch. In this moment relay T1 is energized over: earth, battery, wiper m, contact 371, windings I and II of relay T1, contact 5w, c wiper. of the preselector, c-lead, earth on this lead in the succeeding switch. Relay T1 throws over its contacts 1t1 and 2t1 into the positions. 6221 and H1, by which the aand 6- leads are connected up to the succeeding switch. Further, it closes. its

double front contacts 8t1 and thus breaks the circuit for the rotary magnet D1, with the consequence that the preselector is brought to rest and the subscriber is switchedthrough in a certain traffic direction, by the seizure of the outgoing -abi. and c leads and is connected up, for example, to group selector at his own exchange. V v r p In addition, a circuit for the metering relay Z1 is closed over contact 1000 as follows: earth, battery, wiper. m, contact 8t1, relay Z1, contacts 10%, 500, c-wiper of the preselee tor, c-lead, earth to this, lead in the succeeding switch, with the result that the metering i of the conversation is prepared.

I f the subscriber N1, however, wishes to establish a connection with another exchange,

. he operates a key 'Tal at hisstation in addition to lifting up his receiver, which results in the earthing of the a-lead. The same switching procedures for the starting of the preselector now take place, as were described in the above and effected by the energization of relay R1 but, in addition, however, relay X also is energized. 'This throws-over its contact 5% into the position 800 so that relay T1 tests and is energized over the outgoing cl-lead in a disengaged condition of a succeeding switch, as described in theabove, and results in the connecting up of the al and b1 leadsby-m'eans of the contacts 6151 and 7251 as well as the disconnection of the rotary magnet D1 by the contact 8251. Relay X remains energized over its contact 900 in the following circuit: earth, battery, wiper m, contacts 8151, Sr, winding III of relay X, earth.

, In addition, relay X throws its contact 1050 into the position 1100 and thus closes a circuit for the metering relay Z2 of the meter to be operated for the setting up of a connection in the second traflic direction over: earth, battery, wiper m, contact 8t1, relay Z2, contacts 110a, 8w, cl-wiper of the preselector, cl-lead, earth, on this lead to the succeeding switch so that this conversation, according to its length, is measured by the meter influenced by relay Z2.

The release of the first preselector now follows upon the termination of the conversation'in the ordinary manner.

The arrangement according to Figure 2 operates as follows z-l/Vhen the subscriber N2 lifts his receiver relay R2 is energized over: earth, battery, winding I of relay R2, contact 12252, subscribers line loop, contact 13252, winding II of relay R2, earth. Relay R2 closes its contacts 141 2 and 1512 so that a circuit for the rotary magnet of the first pres-elector is closed over: earth, battery, contacts 1522, 16252, rotary magnet D2, interrupter U12 and earth and this is advanced until its wipers have reached a free succeeding second preselector, when relays T2 in the first preselector and R3 in the second preselector "are energized over: earth, battery, contact 142 2, windings II and I of relay T2, c-wiper of the first preselector, c-lead, contact 17 253, winding I of relay R3, earth- Relay T2 throws over its contacts 16252, 12252, 13252 into the'positions 18t2, 19252, and 20252, with the consequence that the circuit for the rotary magnet D2 is broken and the first preselector is brought to rest. In addition, by the throwing over of contacts 12t2 and 13t2, the relay R2 releases and opens its contacts 1412 and The contacts 2123, 229 3 and 2413 are closed in the second preselector by the energization of relay R3. Relay U cannot respond over contact 2223, due to the resistance W2 but the rotary magnet D3, on the other hand,

is energized over; earth, battery, magnet D3, contacts 2423, 25253, interrupter Ur3, earth, resulting in the second preselector being advanced until it has reached a free succeeding switch. In this moment relay T3 is energized over: earth, battery, contact 18252 in the first preselector, winding I of relay T2, c-wiper of the first preselector windings I and II of relay T3 in the second .preselector, contact 2624, winding II of relay R3, contact'21r3, c-wiper of the second preselector, c-lead, earth on this lead in the succeeding switch. By the .energization of relay T3 contact 17t3 is thrown into the position 27253 and the high resistance winding I of relay T3 then short-circuited with the result that the seized line is guarded against a repeated seizure in known manner. Additionally, the contact 28253 is closed and 25253 opened. By the latter switching procedure the circuit for the rotary magnet D3 is broken and the second preselector is brought to rest. FLlIlJl161,'3.t the energization of relay T3 the contacts 29t3 and 30153 are closed, so that the subscriber is connected up to a group selector in his own exchange.

Should he, however, require a connection in. another traific direction, e. g., to another exchange, he operates the key Ta2 at his station and causes thereby the earthing of the alead. Hereby the differential relay S is caused to operate over: earth, key Ta2, con-' tact 19t2,a-wiper of the first preselector, winding I of relay S, contact 29253, a-wiper of the second preselector,-winding I ofrelay A in the succeeding switch, battery, earth, as its winding II is short-circuited by the pressing of the key. Relay S closes its contact 318 and thereby connects up relay U over: earth, battery, winding I of relay U', contacts 318, 28t3 earth. Relay U throws over its contact 2622 to the position 3222 and by the breaking of the c-lead then causes the release of the succeeding group selector in known manner and also thc'release of the relay T3. Hereby the contacts 25:63 and 17253 are reclosed. Relay R3 remains energized over contact 17253 and the rotary magnet D3 is energized a fresh over contact 25253, so that the second preselector is connected to the line group of the other traflic direction and hunts for a free line in this. Upon finding it, relay T3 is energized afresh over: earth, battery, contact 18252, windingI of relay T2, c-wip'er of the first preselector, windings I and II of relay T3, contact 3220, winding III of relay U, c-wiper of the second preselector, cl-lead, earth to this lead in the succeeding switch. RelayT3 causes the return .of its contact 17253 to the position 27253 and .opens contact 25253 by which the preselector .ing circuit for relay U has been closed over its winding III at the arrival of the cl-wiper to a free succeeding switch when relay R3 is released with slow action.

. The release of the connection is then effected by the replacing of the receiver in known manner. I

What is claimed is;

' 1. In atelephone systein,asubscribers line,

a lineswitch individual to said line, a first and a second group of trunks extending to different zones accessible to said switch, a device located at the subscribers substation, means responsive to the removal of the re ceiver by the subscriber for causing said switch to automatically hunt for and seize a trunk in the first group, and means responsive to the operation of said device and the removal of the receiver by the subscriber for causing said switch to automatically hunt for and seize a trunk in the second group.

2. In a telephone system, a subscribers line, a lineswitch individual to said line, a first and a second group of trunks accessible to said switch, a difierential relay in said switch, a test circuit in said switch, a first test wiper in said switch normally connected to said test circuit and a second test wiper in the switch normally disconnected, a device located at the subscribers substation, means responsive to the removal of the receiver by the subscriber for operating said first test wiper to find a trunk in the first group and connect the subscribers line thereto, means responsive to the operation of said device and the removal of the receiver by the subscriber for operating said diiierential relay to disconnectthe first test wiper from the test circuit and to connect the second test wiper to the test circuit, and for operating the secondtest wiper to find a trunk in the second group and connect the subscribers line thereto. 7

3. In a telephone system, a subscribers line, a lineswitch individual to said line, a first and a second group of trunks accessible to said switch, a differential relay in said switch, a test circuit in said switch, a first test wiper in said switch normally connected to said test circuit and a second test wiper in the switch normally disconnected, a device located at the subscribers substation, means responsive to the removal of the receiver by the subscriber for operating said first test wiper to find a trunk in the first group and connect the subscribers line thereto, means responsive to the operation of said device and the removal of the receiver by the subscriber for operating said differential relay to disconnect the first test wiper from the test circuit and to connect the second test wiper to the test circuit, and for operating the second test wiper to find a trunk in the second group and connect the subscribers line thereto, a first meter relay in said switch for determining the charge for connections over the first group of trunks, a second meter relay in said switch for determining the charge for connections over the second group of trunks, and means controlled by said difierential relay for to different traffic areas, a first meter relay in said switch for determining the charges for connections set up over the first group of trunks, a second meter relay in said switch for determining the charges for connections.

tion.

5. Ina telephone system, a subscribers.

line, a primary lineswitch individual to said line, a plurality of secondary lineswitches accessible to said primary lineswitch, a first and a second group of trunks accessible to said secondary lineswitches extending to diiierent traflic areas, a device located at the subscribers substation, means responsive to the removal of the receiver by the subscriber for operating said primary lineswitch to select'an idle one of said secondary lineswitches, means responsive thereto for automatically operating the selected secondary lineswitch to select a trunk in the first group, and means in said secondary lineswitch responsive to the operation of said device by the subscriber for automatically reoperating said secondary lineswitchto select a trunk in the second group.

6. In a telephone system, a subscribers line, a first and a second group of trunks extending to different trafiic areas, a first and a second metering device individual to said line, a device located at the subscribers station, and means for selecting a trunk in the first group and for preparing said first metering device for operation in response to only the removal of the receiverby the subscriber or for selecting a trunk in the second group and for preparing said second metering device for operation in response to the removal of the receiver by the subscriber only in case said device at the sub-scribers station is operated.

In witness whereof, I hereunto subscribe my name this 27th day of January, A. D. 1931.

REINI-IOLD HOEFERT. In witness whereof, I hereunto subscribe myname this 27th day of January, A. D. 1931.

KURT WOLLACK.

connecting the meter relay corresponding to p 

